The research will examine the effects of phototherapy as used in neonatal jaundice on drug metabolizing enzymes of the liver and skin of jaundiced and normal rats. Congenital jaundice as occurs in the Gunn mutant of the Wistar rat results in impaired fertility believed to result from bilirubin embryotoxicity. While phototherapy is almost exclusively used in the neonate, we intend to examine the effects of phototherapy on reproduction in the jaundiced female rat. It has been reported that the commonly used anticonvulsants, phenytoin and phenobarbital, cause neonatal hemorrhage when given to pregnant mothers. We are seeking an animal model to investigate this reported effect of anticonvulsants. These investigations will utilize cats, rabbits, and possibly, nonhuman primates.